Introduce MvcUtils#decodeQueryString method

Signed-off-by: Yike Xiao <[email protected]>

Author: Shawyeok

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/common/MvcUtils.java

@@ -21,6 +21,8 @@
 import java.io.InputStream;
 import java.io.UncheckedIOException;
 import java.net.URI;
+import java.net.URLDecoder;
+import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collection;
@@ -44,6 +46,7 @@
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StreamUtils;
+import org.springframework.util.StringUtils;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.servlet.function.ServerRequest;
 import org.springframework.web.servlet.support.RequestContextUtils;
@@ -283,15 +286,21 @@ public static MultiValueMap<String, String> encodeQueryParams(MultiValueMap<Stri
 		return CollectionUtils.unmodifiableMultiValueMap(encodedQueryParams);
 	}
 
-	public static MultiValueMap<String, String> decodeQueryParams(MultiValueMap<String, String> params) {
-		MultiValueMap<String, String> decodedQueryParams = new LinkedMultiValueMap<>(params.size());
-		for (Map.Entry<String, List<String>> entry : params.entrySet()) {
-			for (String value : entry.getValue()) {
-				decodedQueryParams.add(UriUtils.decode(entry.getKey(), StandardCharsets.UTF_8),
-						UriUtils.decode(value, StandardCharsets.UTF_8));
+	public static MultiValueMap<String, String> decodeQueryString(String queryString, Charset charset) {
+		String[] pairs = StringUtils.tokenizeToStringArray(queryString, "&");
+		MultiValueMap<String, String> result = new LinkedMultiValueMap<>(pairs.length);
+		for (String pair : pairs) {
+			int idx = pair.indexOf('=');
+			if (idx == -1) {
+				result.add(URLDecoder.decode(pair, charset), null);
+			}
+			else {
+				String name = URLDecoder.decode(pair.substring(0, idx), charset);
+				String value = URLDecoder.decode(pair.substring(idx + 1), charset);
+				result.add(name, value);
 			}
 		}
-		return CollectionUtils.unmodifiableMultiValueMap(decodedQueryParams);
+		return result;
 	}
 
 	private record ByteArrayInputMessage(ServerRequest request, ByteArrayInputStream body) implements HttpInputMessage {

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/filter/FormFilter.java

@@ -49,7 +49,6 @@
 import org.springframework.lang.Nullable;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
-import org.springframework.web.util.UriComponentsBuilder;
 
 /**
  * Filter that rebuilds the body for form urlencoded posts. Serlvets treat query
@@ -114,14 +113,7 @@ static HttpServletRequest getRequestWithBodyFromRequestParameters(HttpServletReq
 		Writer writer = new OutputStreamWriter(bos, FORM_CHARSET);
 
 		Map<String, String[]> form = request.getParameterMap();
-		String queryString = request.getQueryString();
-		StringBuffer requestURL = request.getRequestURL();
-		if (StringUtils.hasText(queryString)) {
-			requestURL.append('?').append(queryString);
-		}
-		UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(requestURL.toString());
-		MultiValueMap<String, String> queryParams = uriComponentsBuilder.build().getQueryParams();
-		queryParams = MvcUtils.decodeQueryParams(queryParams);
+		MultiValueMap<String, String> queryParams = MvcUtils.decodeQueryString(request.getQueryString(), FORM_CHARSET);
 		for (Iterator<Map.Entry<String, String[]>> entryIterator = form.entrySet().iterator(); entryIterator
 			.hasNext();) {
 			Map.Entry<String, String[]> entry = entryIterator.next();